DOCSLIB.ORG

Introduction to the Mechanics of Space Robots (Space Technology

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Introduction to the Mechanics of Space Robots (Space Technology INTRODUCTION TO THE MECHANICS OF SPACE ROBOTS SPACE TECHNOLOGY LIBRARY Published jointly by Microcosm Press and Springer The Space Technology Library Editorial Board Managing Editor: James R. Wertz, Microcosm, Inc., El Segundo, CA, USA; Editorial Board: Val A. Chobotov, Consultant on Space Hazards, Aerospace Corporation, Los Angeles, CA, USA; Michael L. DeLorenzo, Permanent Professor and Head, Dept. of Astronau- tics, U.S. Air Force Academy, Colorado Spring, CO, USA; Roland Doré, Professor and Director, International Space University, Stras- bourg, France; Robert B. Giffen, Professor Emeritus, U.S. Air Force Academy, Colorado Spring, CO, USA; Gwynne Gurevich, Space Exploration Technologies, Hawthorne, CA, USA; Wiley J. Larson, Professor, U.S. Air Force Academy, Colorado Spring, CO, USA; Tom Logsdon, Senior Member of Technical Staff, Space Division, Rockwell International, Downey, CA, USA; F. Landis Markley, Goddard Space Flight Center, NASA, Greenbelt, MD, USA; Robert G. Melton, Associate Professor of Aerospace Engineering, Pennsyl- vania State University, University Park, PA, USA; Keiken Ninomiya, Professor, Institute of Space & Astronautical Science, Sagamihara, Japan; Jehangir J. Pocha, Letchworth, Herts, UK; Frank J. Redd, Professor and Chair, Mechanical and Aerospace Engineer- ing Dept., Utah State University, Logan, UT, USA; Rex W. Ridenoure, Jet Microcosm, Inc., Torrance, CA, USA; Malcolm D. Shuster, Professor of Aerospace Engineering, Mechanics and Engineering Science, University of Florida, Gainesville, FL, USA; Gael Squibb, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA; Martin Sweeting, Professor of Satellite Engineering, University of Surrey, Guildford, UK For further volumes: www.springer.com/series/6575 Giancarlo Genta Introduction to the Mechanics of Space Robots Prof. Dr. Giancarlo Genta Department of Mechanical and Aerospace Engineering Politecnico di Torino Corso Duca degli Abruzzi 24 Torino 10129 Italy [email protected] ISBN 978-94-007-1795-4 e-ISBN 978-94-007-1796-1 DOI 10.1007/978-94-007-1796-1 Springer Dordrecht Heidelberg London New York Library of Congress Control Number: 2011935862 © Springer Science+Business Media B.V. 2012 No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Cover design: VTeX UAB, Lithuania Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) To Franca and Alessandro Preface This text started as a collection of notes of the lectures on Space Robotics given by the author to the students of the International Master on Space Exploration and De- velopment Systems (SEEDS). The aim of the course was the study of the automatic machines aimed to operate both autonomously and as a support to astronauts in space exploration and exploitation missions, with particular attention to the devices designed for planetary environment, including small planets, comets and asteroids. This material was then completed and made more systematic so that it can hope- fully be useful not only to the students of that course but also to those who have an interest in the wide and much interdisciplinary field of space robotics, and in particular in its mechanical aspects. The focus is drawn mainly on the mechanics of space robots: the author is well aware that, even in this specific field, it is far from being complete and that robots, like all mechatronic systems, are so integrated that no single aspect can be dealt sep- arately. Many important aspects are either dealt with only marginally or altogether left out. The very important topics of the control and the behavior of robots, for in- stance, are only marginally touched, even if their influence on the mechanical aspect to which this book is dedicated is not at all marginal. The structure of the book is so organized: • Chapter 1: a very short introductory overview of human and robotic space ex- ploration, stressing the need for man-machine cooperation in exploration. The various types of robotic missions in LEO, deep space and on planets and their basic requirements are shortly summarized. • Chapter 2 deals in a synthetic way with the main characteristics of the environ- ments space robots are facing and will face in the future. Since space environment is a specialized subject, dealt with in many books, this subject is only briefly sum- marized. • The configurations of robot arms and the basic kinematic and dynamic relation- ships needed for their design are described in Chap. 3. • Chapter 4 is devoted to the study of mobility on planetary surfaces, using differ- ent kind of supporting devices, like wheels, legs and aerodynamic or aerostatic devices. vii viii Preface • The basic characteristics of wheeled robots and vehicles are summarized in Chap. 5. The behavior of wheeled devices is studied in its various aspects, like longitudinal, lateral and suspension dynamics. The consequences of operating wheeled machines in the various environments are analyzed in some detail. The chapter is concluded by a description of the only vehicle that successfully carried humans on the surface of the Moon, the Apollo Lunar Roving Vehicle. • Vehicles and robots that use legs, tracks or other devices to move on a solid sur- face are described in Chap. 6. Since a great number of different architectures were proposed and sometimes even used in the past, not all the possible configurations are illustrated: the choice was based on the actual existing applications and on the perspectives of future use. • Chapter 7 is devoted to a short overview of the transducers used for actuation and sensing in space robots. • A short overview of the energy sources and storage devices that can be used for space robots is reported in Chap. 8. The book includes two appendices summarizing the theoretical formulations al- lowing to write mathematical models of space robots including a variety of mechan- ical components, such as arms, legs, etc. The author found it necessary to include them, since the participants to the course in Space Exploration and Development Systems have a much varied background and what may seem obvious to some stu- dents, could be difficult for other ones. In a similar way, some of the readers of this book may not be familiar with the concepts of analytical mechanics or dynamics of deformable bodies used in the text, mainly in Chaps. 3 and 5. The author is grateful to colleagues and students of the Mechanics Department and the Mechatronics Laboratory of the Politecnico di Torino for their suggestions, criticism and general exchange of ideas. Students, in particular postgraduate stu- dents, cooperated to this book with their thesis work and their questions, but mainly with their very presence that compelled me to clarify my own ideas and to work out all details. To all of them goes my gratitude. Last, but far from least, this book could not have been written without the support, encouragement and patience by my wife Franca—advisor, critic, editor, companion and best friend since 44 years. A Note on the Illustrations I have made every effort to seek permission from the original copyright holders of the figures, and I apologize if there are cases where I have not been able to achieve my objective. This applies in particular to figures taken from the web, like Figs. 4.10, 4.35, 4.36, 4.40, 5.2, 6.1, 6.15, 6.17, 6.21, 6.23b, 6.24, 6.25a, 6.28, 6.31a, b, c, 7.18, 7.19 and 7.21. Torino, Italy Giancarlo Genta Contents 1 Introduction ................................ 1 1.1 Robots in Space ........................... 1 1.2 Humans and Robots ......................... 3 1.3 Artificial Intelligence ........................ 7 1.4 Missions for Robots and Manipulators ............... 11 1.4.1LowEarthOrbit(LEO)................... 12 1.4.2 Deep Space ......................... 14 1.4.3 Planetary Surfaces . ................... 14 1.5OpenProblems............................ 16 1.5.1Control............................ 17 1.5.2 Mechanics .......................... 17 1.5.3 Transducers ......................... 18 1.5.4Power............................ 18 1.5.5Communications....................... 18 2 Space and Planetary Environment ................... 21 2.1LowEarthOrbitEnvironment.................... 21 2.2 Interplanetary Medium ........................ 25 2.3InterstellarMedium......................... 27 2.4 Lunar Environment ......................... 29 2.5 Rocky Planets ............................ 35 2.5.1Mars............................. 35 2.5.2Mercury........................... 40 2.5.3 Venus ............................. 42 2.6 Giant Planets ............................. 43 2.6.1Jupiter............................ 45 2.6.2Saturn............................ 46 2.6.3 Uranus ............................ 48 2.6.4Neptune........................... 50 2.7 Satellites of Giant Planets . ................... 51 2.7.1Io............................... 54 ix x Contents 2.7.2Europa............................ 54 2.7.3Ganymede.......................... 55 2.7.4 Callisto ............................ 55 2.7.5 Enceladus, Tethys, Dione, Rhea and Iapetus ........ 56 2.7.6Titan............................. 56 2.7.7 Miranda, Ariel, Umbriel, Titania and Oberon ........ 58 2.7.8Triton...........................
Load more

Recommended publications
  • 3.1 Discipline Science Results
    CASSINI FINAL MISSION REPORT 2019 1 SATURN Before Cassini, scientists viewed Saturn’s unique features only from Earth and from a few spacecraft flybys. During more than a decade orbiting the gas giant, Cassini studied the composition and temperature of Saturn’s upper atmosphere as the seasons changed there. Cassini also provided up-close observations of Saturn’s exotic storms and jet streams, and heard Saturn’s lightning, which cannot be detected from Earth. The Grand Finale orbits provided valuable data for understanding Saturn’s interior structure and magnetic dynamo, in addition to providing insight into material falling into the atmosphere from parts of the rings. Cassini’s Saturn science objectives were overseen by the Saturn Working Group (SWG). This group consisted of the scientists on the mission interested in studying the planet itself and phenomena which influenced it. The Saturn Atmospheric Modeling Working Group (SAMWG) was formed to specifically characterize Saturn’s uppermost atmosphere (thermosphere) and its variation with time, define the shape of Saturn’s 100 mbar and 1 bar pressure levels, and determine when the Saturn safely eclipsed Cassini from the Sun. Its membership consisted of experts in studying Saturn’s upper atmosphere and members of the engineering team. 2 VOLUME 1: MISSION OVERVIEW & SCIENCE OBJECTIVES AND RESULTS CONTENTS SATURN ........................................................................................................................................................................... 1 Executive
    [Show full text]
  • Pheres Giant Planets
    15 pheres Giant Planets Andrew P. Ingersoll H E GIANT PLANETS - Jupiter, Saturn, Uranus, and Nep­ tune - are fluid objects. They have no solid surfaces 201 because the light elements constituting them do not condense at solar-system temperatures. Instead, their deep atmospheres grade downward until the distinction Tbetween gas and liquid becomes meaningless. The preceding chapter delved into the hot, dark interiors of the Jovian planets. This one focuses on their atmospheres, especially the observable layers from the base of the clouds to the edge of space. These veneers are only a few hundred kilometers thick, less than one percent of each planet's radius, but they exhibit an incredible variety of dynamic phenomena. The mixtures of elements in these outer layers resemble a cooled-down piece of the Sun. Clouds precipitate out of this gaseous soup in a variety of colors. The cloud patterns are orga­ nized by winds, which are powered by heat derived from sun­ light (as on Earth) and by internal heat left over from planetary formation. Thus the atmospheres of the Jovian planets are dis­ tinctly different both compositionally and dynamically from those of the terrestrial planets. Such differences make them fas­ cinating objects for study, providing clues about the origin and evolution of the planets and the formation oftl1e solar system. aturally, atmospheric scientists are interested to see how well the principles of our field apply beyond the Earth. For Neptune and its Great Dark Spot, as recorded by Voyager 2 example, the Jovian planets are ringed by multiple cloud bands in 1989.
    [Show full text]
  • Instrumental Methods for Professional and Amateur
    Instrumental Methods for Professional and Amateur Collaborations in Planetary Astronomy Olivier Mousis, Ricardo Hueso, Jean-Philippe Beaulieu, Sylvain Bouley, Benoît Carry, Francois Colas, Alain Klotz, Christophe Pellier, Jean-Marc Petit, Philippe Rousselot, et al. To cite this version: Olivier Mousis, Ricardo Hueso, Jean-Philippe Beaulieu, Sylvain Bouley, Benoît Carry, et al.. Instru- mental Methods for Professional and Amateur Collaborations in Planetary Astronomy. Experimental Astronomy, Springer Link, 2014, 38 (1-2), pp.91-191. 10.1007/s10686-014-9379-0. hal-00833466 HAL Id: hal-00833466 https://hal.archives-ouvertes.fr/hal-00833466 Submitted on 3 Jun 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Instrumental Methods for Professional and Amateur Collaborations in Planetary Astronomy O. Mousis, R. Hueso, J.-P. Beaulieu, S. Bouley, B. Carry, F. Colas, A. Klotz, C. Pellier, J.-M. Petit, P. Rousselot, M. Ali-Dib, W. Beisker, M. Birlan, C. Buil, A. Delsanti, E. Frappa, H. B. Hammel, A.-C. Levasseur-Regourd, G. S. Orton, A. Sanchez-Lavega,´ A. Santerne, P. Tanga, J. Vaubaillon, B. Zanda, D. Baratoux, T. Bohm,¨ V. Boudon, A. Bouquet, L. Buzzi, J.-L. Dauvergne, A.
    [Show full text]
  • The Future Exploration of Saturn 417-441, in Saturn in the 21St Century (Eds. KH Baines, FM Flasar, N Krupp, T Stallard)
    The Future Exploration of Saturn By Kevin H. Baines, Sushil K. Atreya, Frank Crary, Scott G. Edgington, Thomas K. Greathouse, Henrik Melin, Olivier Mousis, Glenn S. Orton, Thomas R. Spilker, Anthony Wesley (2019). pp 417-441, in Saturn in the 21st Century (eds. KH Baines, FM Flasar, N Krupp, T Stallard), Cambridge University Press. https://doi.org/10.1017/9781316227220.014 14 The Future Exploration of Saturn KEVIN H. BAINES, SUSHIL K. ATREYA, FRANK CRARY, SCOTT G. EDGINGTON, THOMAS K. GREATHOUSE, HENRIK MELIN, OLIVIER MOUSIS, GLENN S. ORTON, THOMAS R. SPILKER AND ANTHONY WESLEY Abstract missions, achieving a remarkable record of discoveries Despite the lack of another Flagship-class mission about the entire Saturn system, including its icy satel- such as Cassini–Huygens, prospects for the future lites, the large atmosphere-enshrouded moon Titan, the ’ exploration of Saturn are nevertheless encoura- planet s surprisingly intricate ring system and the pla- ’ ging. Both NASA and the European Space net s complex magnetosphere, atmosphere and interior. Agency (ESA) are exploring the possibilities of Far from being a small (500 km diameter) geologically focused interplanetary missions (1) to drop one or dead moon, Enceladus proved to be exceptionally more in situ atmospheric entry probes into Saturn active, erupting with numerous geysers that spew – and (2) to explore the satellites Titan and liquid water vapor and ice grains into space some of fi Enceladus, which would provide opportunities for which falls back to form nearly pure white snow elds both in situ investigations of Saturn’s magneto- and some of which escapes to form a distinctive ring sphere and detailed remote-sensing observations around Saturn (e.g.
    [Show full text]
  • Icarus 220 (2012) 561–576
    Icarus 220 (2012) 561–576 Contents lists available at SciVerse ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus Ground-based observations of the long-term evolution and death of Saturn’s 2010 Great White Spot ⇑ Agustín Sánchez-Lavega a, , Teresa del Río-Gaztelurrutia a, Marc Delcroix b, Jon J. Legarreta c, Josep M. Gómez-Forrellad d, Ricardo Hueso a, Enrique García-Melendo d,e, Santiago Pérez-Hoyos a, David Barrado-Navascués f,g, Jorge Lillo f,g, International Outer Planet Watch Team IOPW-PVOL 1 a Departamento de Física Aplicada I, Escuela T. Superior de Ingeniería, Universidad del País Vasco, Bilbao, Spain b Commission des Observations Planétaires, Société Astronomique de France, 2 rue de l’Ardèche, 31170 Tournefeuille, France c Departamento de Ingeniería de Sistemas y Automática, E.U.I.T.I., Universidad del País Vasco, Bilbao, Spain d Esteve Duran Observatory Foundation, Montseny 46, 08553 Seva, Spain e Institut de Ciències de l’Espai (CSIC-IEEC), Campus UAB, Facultat de Ciències, Torre C5, parell, 2a pl., E-08193 Bellaterra, Spain f Observatorio de Calar Alto, Centro Astronómico Hispano Alemán, MPIA-CSIC, Calle Jesús Durbán Remón 2-2, 04004 Almería, Spain g Centro de Astrobiología (INTA-CSIC), Dpto. Astrofísica, ESAC campus, PO BOX 78, 28691 Villanueva de la Cañada, Madrid, Spain article info abstract Article history: We report on the long-term evolution of Saturn’s sixth Great White Spot (GWS) event that initiated at Received 25 January 2012 northern mid-latitudes of the planet on December 5th, 2010 (Fletcher, L. et al. [2011]. Science 332, Revised 30 May 2012 1413–1417; Sánchez-Lavega, A.
    [Show full text]
  • Saturnis the Second of the 4 Gas Giants. Like Jupiter It Gives Off More
    Saturn is the second of the 4 gas giants. Like Jupiter it gives off more heat than it gets from the Sun. But unlike Jupiter, it has a magnificent set of rings, and it's so light that it would float in water - if you could find a bath big enough! Saturn is about 120,000 km across. It takes 29.46 years to go around the Sun. Like Jupiter, it spins very rapidly - the day lasts for 10 hours and 39 minutes. It has a similar structure to Jupiter. It has a solid core, which is surrounded by a shell of solid hydrogen, which is in turn surrounded by a shell of liquid hydrogen, and then the giant shell of atmosphere. This atmosphere is made of hydrogen and helium gases, and ammonia, with small amounts of other gases. Like Jupiter, Saturn seems to be a bubbling cauldron of liquid and gas. Like Jupiter, the atmosphere of Saturn is NOT in chemical balance, with some unknown process making trace amounts of various gases. Like Jupiter, Saturn gives out more heat than it gets from the Sun. But the heat is made in a different way. On Saturn, the heat comes from the condensing of helium as it sinks in the atmosphere. In the same way that steam gives off heat as it turns from gas into liquid, so helium gives off heat. This heat is is the power supply for the weather of Saturn. Saturn has fierce winds which travel at some 1,700 km/hr near the equator - 3.5 times faster than the winds on Jupiter.
    [Show full text]
  • Essays Essay on Museum in Modern Era, Museum
    Essays Essay on museum In modern era, Museum approach as a prominent aspect of education and entertainment. It contributes to the attraction of country and beneficial for the enhancement of educational knowledge. There is a tendency to believe that museums must be utilized for entertainment as well as for education. Lets delve deeper into the topic to seek more clarification. To begin with, One of the main arguments in favor of that museums are meant for entertainment because museums are tourists attraction and their aim to exhibit the collection of things which majority of people wish to see. It is favorable to enhance economical growth of a particular country and raise the standard of living due to numerous visitors from various countries. It sounds as adventurous activity and more enjoyable for visitors.Moreover,visitors can get information about history and biography of country. On the other hand, Some people argued that museums should focus on education because its a huge source of knowledge which they did not previously know.Usually this means history behind the museum exhibits need to explained and this can be done in various ways. Some museums employ special guides to give information, while other museums offer headsets so that people can listen to detailed commentary about the exhibition. In this way, museums play an important role in teaching people about history,culture, science and many other aspects of life. In an ultimate analysis, the above argument would indicate that museum must be utilize for both purposes entertainment and education. These both aspects beneficial in different ways.
    [Show full text]
  • PHYS 1401: Descriptive Astronomy Notes: Chapter
    PHYS 1401: Descriptive Astronomy Notes: Chapter 07 CHAPTER 07: THE JOVIAN PLANETS NOTES AND SKETCHES 7.1: OBSERVATIONS OF JUPITER AND SATURN The View From Earth ✦ Jupiter and Saturn are naked-eye objects ✦ Uranus and Neptune can be seen using telescopes Spacecraft Exploration Pioneers ✦ Pioneer 10: Launch Mar 72, Jupiter flyby Dec 73 (data relayed through Apr 02) ✦ Pioneer 11: Launch Apr 73, Jupiter Dec 74, Saturn Sep 79 (daily operation stopped Sep 95) Voyager I ✦ Launched Sep 77 ✦ Jupiter flyby Mar 79 ✦ Saturn flyby Nov 80 ✦ Family Portrait Feb 90 ✦ Still transmitting!!! Voyager II ✦ Launched Aug 77 ✦ Jupiter: Jul 79 ✦ Saturn: Aug 81 ✦ Uranus: Jan 86 ✦ Neptune: Aug 89 Galileo ✦ Launched Oct 89 ✦ Reached Jupiter Dec 95 ✦ Orbit until Sep 03 ✦ Decommissioned by sending it crashing into Jupiter Cassini-Huygens ✦ Launched Oct 97 ✦ Jupiter flyby Dec 00 ✦ Arrived at Saturn Jul 04 ✦ Huygens probe separates for Titan: Jan 05 ✦ Still operational New Horizons ✦ Launched Jan 06 ✦ Jupiter flyby Feb 07 ✦ Headed for Pluto then Kuiper belt 7.2: DISCOVERIES OF URANUS AND NEPTUNE ✦ Uranus: 1781, William & Caroline Herschel use telescope ✦ Neptune: 1846, Adams & Leverrier (independently) use gravity 7.3: BULK PROPERTIES OF THE JOVIAN PLANETS Physical Characteristics ✦ All jovians are much less dense than terrestrials ✦ Saturn is least dense; less dense than water ✦ No solid surface; gaseous atmosphere gets hotter & denser deeper below surface until it becomes liquid ✦ Solid core larger than Earth (not Fe-Ni, probably rocky) Rotation Rates ✦ All are spinning
    [Show full text]
  • 19650022424.Pdf
    General Disclaimer One or more of the Following Statements may affect this Document This document has been reproduced from the best copy furnished by the organizational source. It is being released in the interest of making available as much information as possible. This document may contain data, which exceeds the sheet parameters. It was furnished in this condition by the organizational source and is the best copy available. This document may contain tone-on-tone or color graphs, charts and/or pictures, which have been reproduced in black and white. This document is paginated as submitted by the original source. Portions of this document are not fully legible due to the historical nature of some of the material. However, it is the best reproduction available from the original submission. Produced by the NASA Center for Aerospace Information (CASI) NEW MEXICO S'K'ATE UNIVERSiT`f q OBSERVATORY TE^EPMONE; UN VERSITY PARK ► LAS CRUCES, N. NEW MEXICO JACKSON 6-6611 d807G ' TN-701-66-9 A RAPIDLY MOVING SPOT ON JUPITER`S NORTH TEMPERATE BELT Elmer J, Reese and Bradford A. Smith - $ ------ - CFSTI PRICE(S) $ Hard copy INC) ^^ July 1965 Microfiche (MF) f-5 ff 653 July 65 Supported by NASA Grant Nst;-142 -61 _l n b5 3211) 25 (ACCESSION NUMBER) (TNRU) E /0 s -- A^G EL^S) (COD r X^ / ^^^ (NASA CR OR TMX OR AD NUMBER) (CATEGORY) A RAPIDLY MOVING SPOT ON JUPITER°S NORTH TEMPERATE BELT Elmer J. Reese and Bradford A. Smith New Mexico State University Observatory University Park, New-Mexico A very rapid ch-i f t in the longi tude o f a smal l dai* spot on the south Edge c-e Jupiter's I'forth Temperate Belt (I Bs.
    [Show full text]
  • Lightning Detection in Planetary Atmospheres
    Revised version for Weather Lightning detection in planetary atmospheres Karen L. Aplin1 and Georg Fischer2 1. Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH UK 2. Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, A- 8042 Graz, Austria Abstract Lightning in planetary atmospheres is now a well-established concept. Here we discuss the available detection techniques for, and observations of, planetary lightning by spacecraft, planetary landers and, increasingly, sophisticated terrestrial radio telescopes. Future space missions carrying lightning-related instrumentation are also summarised, specifically the European ExoMars mission and Japanese Akatsuki mission to Venus, which could both yield lightning observations in 2016. Keywords Atmospheric electricity; instrumentation; space science; measurements 1. Introduction Lightning outside Earth’s atmosphere was first detected at Jupiter by the Voyager 1 spacecraft in March 1979 (Smith et al., 1979; Gurnett et al., 1979). Since then, lightning has been detected on several other planets (e.g. Harrison et al, 2008), and it may even exist outside our solar system (e.g. Aplin, 2013; Hodosán et al., 2016). Beyond simple scientific curiosity, there are several reasons to study planetary lightning. The famous Miller and Urey experiment of the 1950s found that electrical discharges generated in conditions mimicking the early Earth’s atmosphere produced amino acids, the starting point for life (e.g. Parker et al, 2011). More recent work has shown that energetic electrons accelerated in the electric fields in Martian dust storms can affect atmospheric chemistry, which may also be relevant for life (Harrison et al., 2016). The possibility of life elsewhere in the universe, and the conditions needed for it, remains one of the biggest scientific questions facing mankind, and provides a major motivation.
    [Show full text]
  • Overview of Saturn Lightning Observations
    OVERVIEW OF SATURN LIGHTNING OBSERVATIONS G. Fischer*, U. A. Dyudina, W. S. Kurth , D. A. Gurnettz, P. Zarka§, T. Barry¶, M. Delcroix, C. Go**, D. Peach, R. Vandebergh , and A. Wesley{ Abstract The lightning activity in Saturn's atmosphere has been monitored by Cassini for more than six years. The continuous observations of the radio signatures called SEDs (Saturn Electrostatic Discharges) combine favorably with imaging observa- tions of related cloud features as well as direct observations of flash–illuminated cloud tops. The Cassini RPWS (Radio and Plasma Wave Science) instrument and ISS (Imaging Science Subsystem) in orbit around Saturn also received ground{based support: The intense SED radio waves were also detected by the giant UTR{2 ra- dio telescope, and committed amateurs observed SED{related white spots with their backyard optical telescopes. Furthermore, the Cassini VIMS (Visual and Infrared Mapping Spectrometer) and CIRS (Composite Infrared Spectrometer) instruments have provided some information on chemical constituents possibly created by the lightning discharges and transported upward to Saturn's upper atmosphere by ver- tical convection. In this paper we summarize the main results on Saturn lightning provided by this multi{instrumental approach and compare Saturn lightning to lightning on Jupiter and Earth. 1 Radio Observations of SEDs by Cassini RPWS Saturn Electrostatic Discharges (SEDs) are short and strong radio bursts that were ini- tially detected by the radio instrument on{board Voyager 1 near Saturn [Warwick et
    [Show full text]
  • A Voyage Round Saturn, Its Rings and Moons Transcript
    A voyage round Saturn, its rings and moons Transcript Date: Wednesday, 2 November 2011 - 1:00PM Location: Museum of London 2 November 2011 A Voyage Round Saturn, its Moons and Rings Professor Carolin Crawford INTRODUCTION Saturn is the most distant planet easily visible to the unaided eye, and as such it has been watched closely since prehistoric times. Its particular mystery was only unveiled when Galileo Galilei first turned his simple optical telescope to it in 1610, and immediately noticed something strange about the planet. At first he guessed that its elongated shape was due to a couple of large moons to either side of Saturn; two years later these had disappeared, only to be replaced by two arched ‘cup handles’ to the planet by 1616. It wasn’t until Christiaan Huygens was able to observe Saturn with a much improved version of a telescope in 1659 that the mystery was resolved, when he identified the two ‘handles’ as a ring encircling the planet. Huygens also discovered Saturn's largest moon, Titan. A few years later, Jean-Dominique Cassini discovered a further four moons of Saturn, and resolved the surrounding ring into a series of rings, separated by gaps – the most apparent of these gaps has since been named for him. Today we have the opportunity to scrutinise Saturn in detail, with the luxury of remote exploration by robotic spacecraft; and yet the planet and its complex system of rings and moons remains intriguing. Saturn has been visited by spacecraft only four times. Three were brief flybys: Pioneer 11 in 1979, followed by Voyagers 1 and 2 in 1980 and 1981.
    [Show full text]